Shoulder Impingement (subacromial impingement)

Introduction

Shoulder subacromial impingement syndrome results in pain, and sometimes weakness and loss of movement of the shoulder with overhead activities and activities working away from the side of the body (reaching).

The subacromial bursa and rotator cuff muscle tendons lie within the subacromial space on top of the shoulder. Subacromial impingement refers to a condition when these tendons are caught when the arm is raised from the side of the body towards and above shoulder height. In the majority of cases subacromial impingement is due to postural, flexibility and muscle imbalances.

Diagnosis

Shoulder impingement is a clinical diagnosis. The pain is usually felt down the side of the shoulder and can extend towards but not beyond the elbow. Pain comes on when the arm is lifted away from the side of the body (painful arc), over head and behind the back. With time, the shoulder may become increasingly stiff with reduced range of movement due to pain.

X-rays or other scans are not routinely required but may be requested to rule out other conditions or prior to considering a steroid injection if there is concern regarding the possibility of a rotator cuff tendon tear.

Management without surgery

Most cases of shoulder impingement can be managed successfully with activity modification, pain killers, physiotherapy and injections. Physiotherapy is the mainstay of treatment and all the other modalities, including injections, are simply to enable you to be pain free enough to carry out your exercise regime to achieve your goals.

Management with surgery

If physiotherapy fails to resolve symptoms for at least six months if not longer, you may be offered surgical treatment. The most common procedure performed for this condition is named, “subacromial decompression”. The subacromial space is cleared of any inflammatory tissue, a ligament that holds the space tight is released and a small amount of bone is shaved away to flatten the bone above the space that might catch the tendons below.

The operation is normally performed under general anaesthetic and a nerve block to provide good pain relief after the surgery. It can also be performed with you completely awake just with a nerve block. This means you can watch the surgery taking place on the screen, you won’t feel drowsy or sick afterwards and you’ll be discharged very quickly after the customary tea and toast! Let us know if you would like to consider awake surgery as only certain lists are set up to provide this service.

After Surgery

Your arm will be placed into a collar and cuff sling and the physiotherapists will tell you what you should do with your shoulder. The surgery is performed as a day case procedure, unless it is not safe to do so. It is common to have swelling because of the surgery and the wounds are stitched. At 10 days following surgery, the stitches and dressings are removed at your GP practise. There really are no restrictions on your range of movement postop but pain will be the limiting factor. Most people end up removing the sling after a couple of days.

Complications

Common risks include bleeding, infection, pain and stiffness in the shoulder.

Specific risks with this operation are

• Failure to get rid of your pain (10-15%)
• Nerve injury (<0.1%)
• Further surgery required if fails to work

Results

85-90% of those undergoing this surgery for impingement get better by around 6-9 months following surgery.